Quadratic Equations Using a Formula

Hi Happy New Year everyone hope you all have had a good one........ I'm doing Maths on New Years Day ..... I'm having a bit of trouble with quadratic equations using a formula. I am using the formula to solve the equations but when I substitute the answers back in the equation the answers don't work....

This is the equation :
4²-3x-2=0

I use the formula :
x = -b ± √ b² - 4ac
_____________
2 a

I substitute the letters for the numbers in the formula so that it looks like

Hi Happy New Year thank you
everyone hope you all have had a good one........ I'm doing Maths on New Years Day ..... I'm having a bit of trouble with quadratic equations using a formula. I am using the formula to solve the equations but when I substitute the answers back in the equation the answers don't work....

This is the equation :
4²-3x-2=0

I use the formula :
x = -b ± √ b² - 4ac
_____________
2 a

I substitute the letters for the numbers in the formula so that it looks like